The present invention relates to a method for estimating rainfall condition (such as heavy rain, shower, light rain, and no rain).
Generally, a rain sensing device is used to sense the presence of rain, presumably to prevent the articles outdoors (such as clothes or grains being dried with sunshine) from getting wet. The theory of existing rain sensing devices is based upon the change of insulation between two metal electrode plates when the device is wet; the circuits of such prior art devices are illustrated in FIGS. 1a and 1b.
A rain sensing device as shown in FIGS. 1a and 1b has two states of output, i.e., indicating whether or not it is raining. When the metal electrodes are wet, the insulation between them will be reduced and used to indicate a raining signal. A disadvantage of this prior art device, however, is that it cannot indicate that raining has stopped because the sensor will still be wet; further, such a device is also unable to sense the volume of rainfall. Although the computer technology has been well developed today, the computer is still unable to provide rainfall information by using the existing sensing device. Therefore, the inventors have developed a method and a sensing device to estimate various conditions, such as light rain, shower, heavy rain or no-rain.